There was bemused laughter from Lord Justice Hobhouse's two fellow judges as he peered over his spectacles at the Japanese stereo device and remarked: "I do not think so."
The three judges, whose average age is 66, are being asked to decide whether the Walkman - the electronic success story of the 1980s, which brought in pounds 3bn sales worldwide - was invented by the son of a German industrialist.
Andreas Pavel, 51, took out a patent in 1977 - two years before the Walkman was launched - for a "portable stereo listening device" to be worn on a belt.
Anthony Watson QC, for Sony, was trying to show that the Walkman, although fitted with a clip, was rarely worn on a belt but mostly fixed on a lapel or dropped in a pocket.
He handed an example up to the judges but it was fitted with a loop and Lord Justice Hobhouse remarked: "You could not use this other than for putting on a belt."
Mr Watson replied: "Well, my Lord, you could put it on your handbag."
Mr Pavel wants Lord Justice Hobhouse, Lord Justice Neill and Lord Justice Aldous to overturn a ruling in the County Patent Court in 1990 that his patent was invalid.
If he is successful, he will claim royalties of up to pounds 100m from Sony and Toshiba for sales in Britain alone.
If he fails, however, he will face legal costs of up to pounds 1m.
Judgment was reserved and is expected to be delivered at the end of next week.